bug#65338: 30.0.50; bibtex: Long url field value and bibtex-font-lock-url-regexp

[Visuwesh]

X-Debbugs-Cc: Roland Winkler <winkler@gnu.org>

I have a bibtex entry that has a long URL

    @Misc{DelhiPlasmaPyrlosis,
      author       = {Central Pollution Control Board, India},
      title            = {Study on Plastic Waste Disposal through ``Plasma
                      Pyrolysis Technology''},
      month            = {oct},
      year             = 2016,
      note             = 
{\url{https://cpcb.nic.in/displaypdf.php?id=cGxhc3RpY3dhc3RlL1BsYXNtYS1QeXJvbHlzaXMtZmluYWwtUmVwb3J0LTIxLTExLTE2LnBkZg},
                      last checked on 15/08/2023.},
      file             = {papers/delhiplasmapyrlosis.pdf},
      url = 
{https://cpcb.nic.in/displaypdf.php?id=cGxhc3RpY3dhc3RlL1BsYXNtYS1QeXJvbHlzaXMtZmluYWwtUmVwb3J0LTIxLTExLTE2LnBkZg}
    }

When I fill the entry with C-c C-q, url lines becomes

      url              =
                      
{https://cpcb.nic.in/displaypdf.php?id=cGxhc3RpY3dhc3RlL1BsYXNtYS1QeXJvbHlzaXMtZmluYWwtUmVwb3J0LTIxLTExLTE2LnBkZg}

This however breaks the buttonisation since the second character class
in bibtex-font-lock-url-regexp does not include newline, only space and
tab.  If I add a newline as below, then the url field value is
buttonised as expected.  Should this be done in bibtex-mode.el as well?

diff --git a/lisp/textmodes/bibtex.el b/lisp/textmodes/bibtex.el
index 394f80f47e..96597ba8fb 100644
--- a/lisp/textmodes/bibtex.el
+++ b/lisp/textmodes/bibtex.el
@@ -1845,7 +1845,7 @@ bibtex-font-lock-url-regexp
   ;; Assume that field names begin at the beginning of a line.
   (concat "^[ \t]*"
           (regexp-opt (delete-dups (mapcar #'caar bibtex-generate-url-list)) t)
-          "[ \t]*=[ \t]*")
+          "[ \t]*=[ \t\n]*")
   "Regexp for `bibtex-font-lock-url' derived from `bibtex-generate-url-list'.")
 
 (defvar bibtex-string-empty-key nil


In GNU Emacs 30.0.50 (build 8, x86_64-pc-linux-gnu, X toolkit, Xaw
 scroll bars) of 2023-08-10 built on astatine
Repository revision: 65f71ca9aaa1587284293e2e34a0e28ee6b42380
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
System Description: Debian GNU/Linux trixie/sid

Configured using:
 'configure --with-sound=alsa --with-x-toolkit=lucid --with-json
 --without-xaw3d --without-gconf --without-libsystemd --without-cairo'
Configured features:
ACL DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG JSON
LIBOTF LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP X11 XDBE XFT
XIM XINPUT2 XPM LUCID ZLIB
Important settings:
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  value of $LC_NUMERIC: ta_IN.UTF-8
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Major mode: ELisp/l

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  auto-composition-mode: t
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  auto-compression-mode: t
  abbrev-mode: t

Load-path shadows:
None found.

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Memory information:
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